Oil. A portfolio dominated by it bubbles when prices are up and
sinks downward when they're not.

For emerging-market enthusiasts, ING's Russia
Fund (LETRX) has been one of that category's top performers.
Ranked No.1 in performance history in five of the past seven years
by Morningstar, this fund of some 35 holdings got its high marks
thanks to black gold and other resource-type stocks. (As of late
August, ING's Russia Fund holdings had about 43.74 percent of
assets invested in oil and gas companies.)

"We've had a very good run," says Sam Oubadia, one
of the fund's portfolio managers. Oubadia is a fan of Russian
equities because it's one of the largest emerging markets
around, valuations are still cheap, and Russia attracts a lot of
global investors. But the Russian market tends to be more volatile
than your average emerging market. Oubadia warns investors to
"be aware that the transparency and level of corporate
governances are not the same as in developed markets."

Dian Vujovich is an author, syndicated columnist and
publisher of fund-investing site www.fundfreebies.com.